Color photographic multilayer material



April 28, 1942. B. GASPAR COLOR PHOTOGRAPHIC MULTILAYE IR MATERIAL Filed July 12, 1939 SILVER HALIDE BLUE SENSITIVE SILVER HAL IDE GREEN sENsI'rIvE SILVER HALIDE RED SENSITIVE SUPPORT DYED WITH YELLOW AZO DYE AND DYED WITH MAGENTA AZO DYE HAVING THE GENERAL FoRNIuLA BELA I GASPAR UNITED STATES PATENT oFFlca Bela Gaspar, Brussels-Forest, Belgium, assignor to Chromogen, Incorporated, a corporation of Nevada,

Application July 12, 1939, Serial No, 284,104

In Germany July 1 2, 1938 3 Claims. (01.95-2) In my Letters Patent 2,183,394, granted De cember 12, 1939, a multi-iayer material for color photographic exposures has been described in which the emulsion layer which during the exposure faces the camera lens consists of a colorless blue-sensitive silver halide emulsion behind which follow a green-sensitive and a red-sensitive layer, the green-sensitive layer containing a yellow dye and the red-sensitive layer a magenta dye. During the exposure these dyes act as light-filters; the yellow dye, for example, excludes the blue light rays from the exposure of the green-sensitive layer and allows only the I green and red lightrays to enter and penetrate this layer in such a manner that the green light so that the part of the ,dye not destroyed remains as the image. For this purpose several azo dyes have already been named as useful.

Apart from therequirements which every dye by itself must fulfill in consideration of the above described conditions it has been found that for the preparation of taking materials of a very high speed it is not a matter of simply employing two dyes each one of which, considered alone shows the necessary filter properties and the necessary stability to the usual treating baths, and

. the necessary property of being bleached out in second one, it is obvious that in a taking material in which the exposure times for all layers are equal, it is always the more unsuitable dye which ferior. I

A large amount of comprehensive research work has been carried out on an extensive series for this purpose while the rest were unknown for thls purpose, to examine their suitability and especially to determine which yellow dyes influence the green sensitivity of the emulsion the least and which magenta dyes influence the red sensitivity of the emulsion the least. On the basis of the results of this investigation dyes have been iound which employed in the different layers yield a sensitivity as equally high asposslble in all of the layers. By means of these experiments it has been found that in a gi'eatnumber of cases the sensitivity oi' the light-sensitive silver halide emulsions-apart from decrease of sensitivity for light rays of complementary color produced by the filter eflect-is reduced the least by such azo dyes which do not contain phenolic hydoxy groups in their molecule.

The best results have been obtained by the use of acid dyes'of the following general formula:

in which R1, Rz, R3 and R4 are aromatic radicals, at least one of which contains an acid substituent and at least one of which contains a basic nitrogen substituent or a phenolic hydroxy group but in which not more than one radical contains simultaneously a sulphonic acid substituent and a phenolic hydroxy group, A representing a direct linkage or one of the groups CH=CH and NI-I-CO-NH between the radicals R2 and Rs.

As a matter of fact, it is possible with the aid of such dyes, i. c., if everyone of the colored layers contains a dye corresponding, to the above given general formula, to prepare a light-sensitive color photographic taking material whose sensitivity in spite of the presence of the dyes is hardly reduced as compared with thesensitivity of an undyed material and which has practically as high a sensitivity as it is possible to obtain with the technique employed at present in the preparation of silver'halide emulsions.

Azo dyes which correspond to the general formula and which can be used for the preparation of the material are, for example, the red dyes Direct red 43 (Schultz Farbstofftabellen, Leipzig 1931, 7th ed., vol. 1, No. 448), Hessisch Purpur NN (Schultz l. c. No. 722), Dianol brilliant red R extra (Schultz l. c., No. 425), Benzopurpurine 10 B (Schultz l. c., No. 489), Congo corinth B (Schultz l. c., No. 447) Rosazurin BB (Schultz, l. c., No. 437), Rosazurin B (Schultz l. c.,. No 456), and the yellow dyes Milling Yellow (3 (Schultz l. c., No. 726), and Pyramine orange 2R (Schultz l. c., No. 364); The dyes are prefx of dyes, some of them having already been known 55 erably' employed in the form of their insoluble 2 i salts, especially in the form of their salts with irorganic bases, for example, diphenylguanidine,

or their calcium salts. It should be noted that the use of Milling Yellow G for coloring silver halide emulsions has already been described.

But since the other dyes used together with this dye were far less suitable, the full advantage could not be obtained from the efliciency of the dye Milling y ellow G. p R A The the *diawing represents aicross sectionof a p otographic material wherein the if prepared according to the present invention ,it

gives three separate'irecords, which 'togethefare All of the color separation records are substansupport and respective layers are drawn to an exaggerated scale to illustrate the invention.

As shown in the figure, a red-sensitive magen-f ta colored silver halide layer I is placed upon a an embodiment of v support 2 and a green-sensitive yellow colored silver halide layer 3 is superposed thereon. A

colorless bluesensitive, silver halide layer 4 is,

shown in the figure superposed 'on the greensensitive layer 3 to complete the multi-layer ma terial.

t V The red-sensitivelayer l is prepared from a high sensitive negative emulsion which sensitized with naphthothiocarbocyanine, vselenocarbocya- -nine or another sllitable panchromatic or red .sensiti zer. Tothis-emuls'ion =a 2 -per cent so- ;rllution-of Benzopurpurine B (Schultz-l. c., No.

89) is added-in anamount such that in the finshed coatedlayer 0.6 gram of the dye is contained in a square meter and that the layer shows-with light of the, wave length 525 [L14 an loptical; density of 2.2

The greenesensitive-r-emulsion layer 3 is pre pared from a highly sensitive emulsion of the same kind which was used for the preparation of the red-sensitiveemulslon. To thisemulsion is: added a 1% solution of. Milling Yellow G in I an amount which corresponds to a dye content of 0.75 gram per square meter. At this dye concentration the layer shows with light of the wave .between high lights and d pestv shadows. By 10.;

the use or emulsions having a higher inherent speed a three-layer exposure material can be produced, which does not require longer exposure than a black and white film of 27 Sch.

'. If necessary,-the single emulsion layers can be divided from each other by thin colorless intermediate l'ayers;

Sometimes itnot necessary to precipitate the dyes in the ayer,- -namely, ii the dyes adhere as such ,sufliciently last to the gelatin. For the precipitation especially guanidine derivatives are The dyes used are preferably disazo dyes and length 460 [LIL an optical density of about 2.2.

After the addition of the dye there isadded to the emulsion a solution of diphenylguanidine acetate whereby the dye is converted into the in- I soluble dipherlylguanidine salt. The emulsion is sensitized for green: light with thio-pseudocyanine.'

"The colorless blue-sensitive emulsion layer 4 is prepared from a blue sensitive highly transparent negative emulsion Whd'se sensitivity is about half as-hig h as the sensitivity of the highly sensitive negative emulsion used for the prepara W of the otherItwolayers and which has a speed of about 25 to 26? Sch. Thethree emulsions are either coated superimposed to each other on one sideof atransparent support asshown in the, drawing or the bluesensitive or the red-sensitive emulsion -is coated 'onone side of the support and the two other layersionthe other side 01' the support in such a mannerthat flrstly the blue-sensitive, secondly the g reen sensitive layer and-finally the red-sensitive emulsion layer liesin the direction of the incident light. For the preparation of the layers there areemployed per square meter about 140 cc. or the blue-sensitive and the red-sensitive emulsion and about 220 cc. of-the green-sensitive emulsion. Whereas a panchromatic film .for ordinary 0rd of all color values. a color photographic three layer exposure material records the three p fi mary colors separately in the three layers, but

1 black and white photography yieldsa joint rec- 01; the benzopurpurine dyev type. What is claimed is: 1. A light-sensitive exposure'material for color photographic purposes comprising three lightsensitive silver halideemulsion layers sensitized predominantly-toblue, green and red light. re-

.spectively and" arranged the onev behind the other, a yellow azo dye in-the layer predominantly' sensitized to green light and amagenta azo dye in the layer predominantly sensitized to red corresponding to v the general formula lighlgboth the yellow dyeand the magenta dye in which R1, R2, Ra Rr are"aromatic radicals, at

least one of the said radicals containing an acid substituent and at least one of said radicals containing a substituent selected from the group consisting of basic nitrogen substituents and phenolichydroxy groups, but not more than one Y of the radicals R1, R2, R3, R4 containing simulhalide emulsion dyed .yellow by the dye Chrysophenineanda red-sensitive silverhalide emulsion dyed magenta by a Benzopurpurine dye, the blue-sensitive emulsionlayer having a speed of more than 24 Sch., the green-sensitive emulsion and the red-sensitive emulsion-having for green light and red light respectively, a speed which is suiiicient, to record green and red light intensity ranges substantially equal to the rangeoi' blue light intensities recorded by the blue-sensitive'layer.

3. A light-sensitive exposure material for color photographic purposes comprising three light. sensitive silver halide emulsion layersin superposition, one layer being undyed and sensitive to blue light and having a speed 01 at least 24 8011., the secondlayer being dyed yellow by a reducible yellow azo dye and being predominantly sensitiveto green light, the thirdlayer beingdyed by a reducible magenta azo dye and being predomiyellowanodyeandthereduclblemagentaazo dye corresponding to the general formula I in which R1, Ra, Ra, R4 are aromatic radicals,. 5

at least one of the said radicals containing an acid substituent and at least one ofsald radicals containing a substituent selected from the group consisting of basic nitrogen substituents and taneously. a sulphonic acid' substituent and a phenolic hydroxy group, and in which the direct replaced by one of the groups CH=CH and NH-CO-NH-, the multilayer material havin: such a speed that by the exposure there are recorded in all of the layers silver images which are together equivalent to the silver image recorded by an identicall exposed panchromatic phenolic hydroxy groups, but not more than one 10 black and white film of more than 24 Sch.

of the radicals R1, Ra, Ra, B4 containing simul- BELA GASPARI. 

